Conventionally, there has been widely known, as this type of a damping force control apparatus, the one in which a virtual vehicle model having mounted at a virtual point at the inner side of the turning locus a lift-suppression-use shock absorber for suppressing a lift-up of a vehicle body and a roll-suppression-use shock absorber for suppressing a roll of the vehicle body is adapted to an actual vehicle model having shock absorbers disposed between the vehicle body and each of four wheels, as disclosed in the Japanese Patent No. 3509544.
In this damping force control apparatus, a difference is produced between the total of the damping forces generated by the shock absorbers at the outer wheels of the turning locus and the total of the damping forces generated by the shock absorbers at the inner wheels of the turning locus so as to set the damping force of the shock absorbers at the inner wheels of the turning locus relatively higher than the damping force of the shock absorbers at the outer wheels of the turning locus, in order to suppress the roll of the vehicle body as well as to suppress the lift-up of the vehicle body at the inner wheels of the turning locus. Therefore, the rise of the vehicle at the center of gravity during the turning is suppressed, so that the roll of the vehicle body is suppressed. Consequently, driveability during the turning of the vehicle can be enhanced.
Meanwhile, during the turning of the vehicle, jack-up force is exerted on the vehicle body, i.e., force in the direction of lifting up the vehicle body is exerted on the vehicle body due to the geometry change of a suspension system caused by lateral force produced on the wheels. In the damping force control apparatus disclosed in the Japanese Patent No. 3509544, the damping coefficients of the lift-suppression-use shock absorber and the roll-suppression-use shock absorber are suitably set by considering the jack-up force, whereby the driveability can be enhanced even if the jack-up force is exerted on the vehicle body.
However, in the damping force control apparatus disclosed in the Japanese Patent No. 3509544, the damping forces of the front-wheel-side shock absorbers corresponding to the front wheels and the damping forces of the rear-wheel-side shock absorbers corresponding to the rear wheels are independently controlled, in which the balance of the input applied to the front-wheel-side vehicle body and the rear-wheel-side vehicle body in the vertical direction is not at all considered. Therefore, a difference is caused between the jack-up forces exerted on the front-wheel-side vehicle body and the rear-wheel-side vehicle body, or between the inputs applied to the front-wheel-side vehicle body and the rear-wheel-side vehicle body in the vertical direction due to the vehicle structure and weight balance, so that a problem of occurring a pitching during the turning of the vehicle arises.